Injection technique and injection devices play important roles in the treatment of diabetes, and they are even of equal importance with the choice of an insulin preparation and affect success or failure of glycemic control. Many health care workers and diabetic patients on insulin therapy often ignore the influence of the injection technique itself on the effect of the glycemic control. Clinicians often investigate the reasons why the desired glucose control target is not achieved from the insulin preparation and blood glucose self monitoring point of view, while neglecting the influence of the injection technique itself on the effect of the glycemic control. The process of insulin being injected into a human body by means of the injection device and functioning is of great importance. Insulin absorption rate differs for insulin subcutaneous injection or for insulin intramuscular injection, because absorption rates of insulin differ a lot at different injection locations, and insulin absorptions differ a lot in a stationary state and in a moving state. Optimizing insulin injection technique includes choosing a needle head with an appropriate length, using correct injection technique, regularly changing injection sites, and avoiding intramuscular injection, etc. All these are of great importance for the glucose control.
A research on insulin injection technique situation in China reveals that, for about 31.1% of patients, injection results in a bump at a corresponding injection site, of which 90% are at abdomen. However, there is still part of patients receiving injection at fat tissue hyperplasia sites. Performing injection at the same site repeatingly will cause subcutaneous fat tissue hyperplasia at this site and then a sclerosis generates. Insulin absorption reduces if insulin is injected once again at this site, and absorption of insulin lasts too long results in an unstable glycemic control. The research also reveals that, for about 30% of patients, the skin is not pinched during the injection being performed at abdomen. If it is a needle head of 8 mm that is used in this case, a potential risk of intramuscular injection may be caused, which will accelerate the insulin absorption and adversely affect the effect. Meanwhile, for half of the patients, although the injection is performed with the skin pinched, but the skinfolds are released prematurely. In fact, other than abdomen, other sites of a human body such as lateral thigh, lateral ¼ location of arm and buttock are also suitable for insulin injection. Regularly changing injection sites means regularly changing injection sites among abdomen, arm, thigh and buttocks. Treatment effect can be improved and complication probability can be reduced by regularly changing injection sites. Injection angles and injection methods vary due to different lengths of insulin injection needle heads. Injections should be performed with a 45 degrees angle and with the skin pinched if the needle head adopted has a length of 8 mm or 12.7 mm, in order to increase the thickness of subcutaneous tissue and to reduce the risk that insulin being injected into an intramuscular layer. Injections can be performed vertically without needing to pinch the skin if an ultra-thin and ultra-short needle head of 5 mm length is adopted, as long as the entire needle head pierces into the subcutaneous tissue. Pain can be alleviated and injection adherence can be improved with the needle head of 5 mm.
Insulin pen injection is widely used on patients with diabetes due to its properties of easy to learn, accurate dose, convenient and durable, slight pain, good effect, etc. In clinical Applications, injection is performed by means of a novo pen and a HumaPen Ergo II in cooperation with a needle head of 8 mm×30 G. According to operating instructions, the needle head should stay in the skin more than 6 s to 10 s after injection while a push button is pressed down, until the needle head is pulled out. During practice, due to medicine liquid injected subcutaneously can not be diffused and absorbed fully in a short time, a little medicine liquid drops off the needle head even if the operation is performed according to the operating instructions. Thus, the accuracy of treatment dose can not be guaranteed.
A needle tube of an existing disposable injection needle head generally has a length more than 15 mm, and even an ultra-fine needle tube of 0.25 mm diameter deployed in a disposable injection needle head for an insulin pen has a length up to 4.5 mm to 12 mm. In this case, vertical injection can not be directly performed at locations, for example at arm, if the skin is not pinched, and patients especially children are terrified by the pain caused by the injection. Due to only one needle tube for one needle head, for the same dose to be injected, although a shorter needle tube may cause alleviated pain, the needle head has to stay in the skin during the injection and after the injection, and the time it will take for the medicine liquid to be sufficiently absorbed during which the patients have to wait will consequentially increase. These factors will undoubtedly bring much inconvenience to the patients. As a result, it is easier said than done, and the patient adherence to proper treatment regimen is reduced and thus the effect is adversely affected.
In addition, a disposable injection needle head on the existing insulin pen has to be used in combination with the insulin pen, and the disposable injection needle head and the insulin pen are stored separately from each other when not in use and assembled temporarily when in use. As a result, the whole injection device is bulky and heavy and thus is only applied to insulin injection.